The Maryland chapter of the American Chestnut Foundation's breeding program in Columbia aims to keep the blight-resistant specimen blooming

A rare tree grows in Md.

September 20, 2006|By Karen Nitkin | Karen Nitkin,special to the sun

As recently as a 100 years ago, it has been said, a squirrel could travel from Maine to Georgia without touching the ground, by hopping from one American chestnut tree to another.

But a blight that was first discovered at the Bronx Zoo in 1904 has killed more than 4 billion of the trees and left most of the others too sickly to grow past a few feet tall.

So when Columbia residents Larry and Gwen Peters spotted an American chestnut tree growing along Harper's Farm Road, it was a big day for the Maryland chapter of the American Chestnut Foundation.

The foundation, formed in 1983, is working to bring back the majestic tree through an ambitious breeding program designed to create future generations that are blight-resistant. When a tree like the one on Harper's Farm Road is discovered, it has proved that it is at least somewhat blight-resistant, so it is recruited for the breeding program.

"What's somewhat rare is to find an old survivor, a tree that has blight but is still able to produce the flowers and the nuts," said Essie Burnworth, president of the Maryland chapter. "They almost all have some blight, but the fact is it hasn't stopped the tree from blooming and growing."

Bags were placed around 166 of the tree's flowers in June to protect the young buds from being pollinated by the wrong specimens. A couple of weeks later, the bags were removed and the flowers were brushed with pollen from the foundation's Meadowview Research Farm in Virginia. The bags were then put back on the flowers to protect them and to help the experts keep track of which ones were pollinated.

Yesterday, about a dozen people, mostly members of the chapter, watched as Robert Strasser, chairman of the chapter's research committee, and David Campbell, the horticulturist with the Columbia Association, stood on a crane and snipped the bags from the tree. Inside most were burs covered in spiny grass. Inside the burs were the nuts that will be used to make disease-resistant trees.

"We're pretty confident we have a successful cross here," Strasser said, standing on the lowered crane after the bags had been removed.

The nuts will be cleaned and stored for the winter, then planted in special American Chestnut Foundation orchards - a vital link in the program.

This year, said Burnworth, 12 trees have been found and pollinated in Maryland. Each one will yield between 100 and 200 nuts. In all, three American chestnut trees are known to exist in Howard County. But the one on Harper's Farm Road, about 12 inches in diameter and 30 feet high, is one of the largest in the state - in the "top three or four in terms of diameter," said Gary Carver, head of the chapter's location committee.

Not so long ago, an American chestnut that large would not have been noteworthy. The American chestnut was once one of the most common trees in America, flourishing all along the East Coast. It grew straight and tall, like a redwood, and had excellent wood, still in evidence in the form of fences along the Blue Ridge Parkway and telephone poles on Cape Cod, Burnworth said.

Then, in the late 1800s, an Asian chestnut tree was brought to America because it had a meatier nut (though not as sweet, say some American chestnut devotees).

The Asian tree thrived. Its nuts are the ones that people eat today. But the Asian tree, though resistant to the blight, brought the disease that began to destroy its American counterpart. By the 1950s, American chestnuts were nearly gone.

"It was an environmental catastrophe," Burnworth said.

For a long time, it seemed that nothing could be done. Then a group of scientists formed the American Chestnut Foundation, with the breeding program as its cornerstone.

"The goal is to reintroduce the tree," Carver said.

Maryland is one of 15 states along the East Coast with chapters of the American Chestnut Foundation. Members and other people knowledgeable about chestnuts look for the trees. Carver said about 50 "larger" trees - at least four inches in diameter - have been verified in Maryland, including the three in Howard County. About 20 Maryland trees are 10 inches or larger.

The larger the tree, the more desirable it is for the breeding program because it already has resisted the blight, Carver said. The Columbia tree is "one of the biggest," he said.

Burnworth said she would take the burs home and store them for several days until they opened. Her husband, Burnie, vice president of the chapter, would then open the seeds to remove the nuts. From there, the nuts will be bathed in 120-degree water for 20 minutes to remove weevils, and then they will be packed in peat moss and refrigerated until spring in labeled bags inside a dedicated refrigerator. In March 2007, the nuts will be planted in one or more of the foundation's dedicated orchards.

Essie Burnworth said the first generation of genetically blight-resistant trees has been created, but it is too early to tell if they will grow successfully. Burnie Burnworth said a quicker solution to the problem might come in the form of DNA modification.

Old-school foundation members oppose that plan because they do not want to create genetically modified trees.

But no matter how the blight-resistant trees are created, eventually they will be added to the mix of trees that are used when swatches of clear-cut land are re-forested.

"It'll probably be 100 to 150 years before we know if we're successful," said Essie Burnworth.

But she noted that people often feel helpless in the face of environmental disasters, and working to reverse this particular disaster is satisfying.